Perfume composition containing 2-(2-methyl-1-propenyl)-2, 4, 6-trimethydihydro-4, 5-pyran



United States atent O 3,309,276 PERFUME COMPOSITIGN CQNTAENING 2-{2-METHYL 1 PRUPENYL) 2,4,6 TRIMETH- YLDIHYDRO-4,5-PYRAN Arno Cahn, PearlRiver, N.Y., and Donald Ross Winnegrad, West Englewood, and Allan H.Gilbert, Cresskill, N.J., assignors to Lever Brothers Company, New York,N.Y., a corporation of Maine No Drawing. Filed Oct. 21, I963, Ser. No.317,779 4 Claims. (61. 167-94) This invention relates to a process forpreparing a perfume. More particularly, it relates to a perfume and aperfume blend therefrom.

It is known that dihydropyran compounds can be provided by reacting anunsaturated alcohol with a ketone or an aldehyde (U.S. Pats. Nos.2,422,648 and 2,452,977). It is also known that dihydropyran compoundscan be provided as a by-product in the dehydration of a glycol to adiene (US. Pat. No. 2,422,802). Other methods for preparingdihydropyrans or pyran derivatives are disclosed in U.S. Pats. Nos.2,514,168, 2,365,623, 2,603,650, 2,976,299, 2,858,322, 2,610,193,2,576,323 and 2,868,805. The aforementioned dihydropyrans have beenemployed as insecticides; fungicides; parasiticides; solvents;biologically active materials; chemical intermediates; and reagents andadditives for resins, plastics and rubbers.

It has now been discovered that a certain dihydropyran imparts anintense top note to rose and enhances the rose note of a perfume :blend.Thus, in accordance with one embodiment of this invention, a perfume hasbeen provided having the following structure:

\CH=C(CHJ)2 As defined herein, this structure, i.e.,2-(2-methyl-l-propenyl)-2,4,6-trimethyldihydro 4,5 p-yran, includes thestructure isomeric therewith.

For the success of the present invention, it is necessary to have2-methyl-1-propenyl in the 2-position. For example, if the 2-positionhas n-hexyl or i-butyl, the dihydropyran therefrom is not a perfume.Dihydropyrans with other substituents in the ring, e.g., 2-i-butyl-4,6-dimethyldihydro-4,5-pyran and 2-(1-propenyl) 4,6dimethyldihydro-4,5-pyran, also do not have any perfumy properties.

A second embodiment of this invention is the process for preparing theperfume 2-(2-methyl-1-propenyl)-2,4,6- trimethyldihydro-4,S-pyran. Ithas been found that this perfume may be provided by reacting2-methyl-2,4-pentanediol directly with mesityl oxide in a homogeneousaqueous solution. Therefore, a separate step is not required in this insitu process to form 4-methyl-4-pentene- 2-ol as an intermediateproduct. The reaction is generally conducted in the presence of an acidcatalyst, e.g., sulfuric acid, with refluxing. After the reaction iscomplete, e.g., after 24 hours, the solution therefrom is cooled,neutralized and distilled to form 2-(2-methyl-1-propenyl)-2,4,6-trimethyldihydro-4,5-pyran, a perfume.

One of the reactants in the present invention is mesityl oxide. Thisketone having the structure:

is externally prepared by any method known in the art. A suitablemethod, for example, is the dehydration of diacetone alcohol. The otherreactant herein is 2-methyl- 2,4-pentanediol having the structure:

This diol may also be prepared by any known method.

Although 2 (2-methyl-1-propenyl)-2,4,6-trimethyldihydro-4,5-pyran aloneis considered to be a perfume, it is generally employed in combinationwith other perfumes as a perfume blend. This perfume blend is a thirdembodiment of the instant invention. A suitable composition, forexample, may be provided by blending 1 to 50 parts of2-(2-methyl-1-propenyl)-2,4,6-trimethy1dihydro- 4,5-pyran with parts ofother perfumy materials. Any known perfumes may be used in the blendwith 2- (2 methyl-l-propenyl)-2,4-trirnethyldihydro 4,5 pyran. Asdefined herein, a perfume is a substance, natural or synthetic, thatemits a pleasant fragrance, i.e., an agreeable odor, which is usually afluid preparation used for scenting. This includes the followingcompounds among others: citronellyl formate, citronellol, labdanumresin, nerol, menthone, geraniol, trans-decahydro-,8-nap-hthol,benzoylphenone, artificial musk, phenyl ethyl acetate, benzyl acetate,ionone, phenyl ethyl alcohol and mixtures thereof. However, thepreferred perfume blends are those which have an intense top note torose; for example, a blend of2-(2-methyl-1-propenyl)-2,4,6-trimethyldihydro-4,5-pyran, citronellol,geraniol, phenyl ethyl alcohol, ionone, and benzyl acetate. As definedherein, top note to rose includes the geranium note.

Thus, in accordance with this invention, a synthetic perfume has beenprovided. It is significant that this perfume, i.e.,2-(2-methyl-1-propenyl)-2,4,6 trimethyldihydro-4,5-pyran, can be formeddirectly from a diol reactant thereby eliminating a step heretoforeemployed for preparing dihydropyransin general.

- Furthermore, it is now possible tomanufacture a perfume compositioncomprising 2-(2-methyl-'1-propenyl)- 2,4,6-trimethyldihydro-4,S-pyranand another perfumy compound A surprising and unexpected feature of thisinvention is the discovery that 2-(2-methyl-1-propenyl)-2,4,6-trimethyldihydro-4,S-pyran has the unique property of impartingstrength and brightness to a rose blend which,

without 2-(2-methyl-l-propenyl) -2,4,6-trimethyldihydro- 4,5-pyran,would be relatively weak. 2-(2-methyl-1-propenyl)-2,4,6-trimethyldihydro4,S-pyran may also be useful in covering the pungent odors of petroleumand other hydrocarbons. Moreover, 2-(2-methyl-1-propeny1)-2,4,6-trimethyldihydro-4,5-pyran is stable in alkaline liquid media, e.g.,soaps and detergents.

The following examples are submitted to illustrate but not to limit thisinvention. Unless otherwise indicated,

all parts and percentages in the specification are based on weight.

Example I Mesityl oxide (98 g., 1 mol) and 2-methyl-2,4-pentanediol g.,1.1 mol) were refluxed for 24 hours in 1 ml. of concentrated sulfuricacid and 5 ml. of water. The solution therefrom was cooled, neutralizedwith alcoholic sodium hydroxide and distilled to yield 45 g. (25%) of anoil (B.P. 72-83 C./l1 mm.). This oily reaction product, i.e.,2-(2-rnethyl-l-propenyl)-2,4,6-trimethyldihydro- 4,5-pyran, was a lightyellow perfume.

4,5, pyrau 3 Example II The compounds indicated in Table l were alsoprepared.

TABLE I R Substitu ent i-butyl l-propenyl n-hexyl.

None of the compound in Table I were considered to be perfumes.

Examples I and II demonstrate the criticality of having on dihydropyrana 2-r'nethyl-1-propenyl substituent in the 2 position and "methylsubstituents in the 2,4,6-positions in order to have the desiredodoriferous properties.

. Example 111 Perfume compositions were formed from 2-(2-methyl-.l-propenyl)-2,4,6-trimethyldihydro-4,5-pyran and other compounds. Thesecompositions are indicated in Table -11 hereoelow.

TAB LE 11 Compositions Parts Ingredients Oitronellol 200 400 Gernniol100 Phenyl ethyl alcohol .s 200 Ionone 30 Benzyl aoetate 100Benzoylphenone 100 Phenyl ethyl ace -60 Artificial musk l- 10 2(2methyl-1-prop enyl) -2,4, Mrimethyld ihydro-.

Both Composition 1 and Composition 2 had an intense top note to rose.Example 1V The perfume blend shown in Table HI is considered to have astrong, bright rose note r TABLE III Parts by weight Ingredients:

2-(2-rnethyl-1-propenyl)-2,4,6-trirnethyldihydro- 4,5-pyran 2 l5Gcraniol 10 Nerol l Citronellol 50 Menthone Citronellyl formate Havingset forth the general nature and specific embodiments of the presentinvention, the true scope is now particularly pointed out in theappended claims.

What is claimed is:

1. A composition comprising a blend of at least two perfumes in whichone perfume has the structure:

(Illa (J 11 0 o c H=C(CH3)1 2. A perfume blend comprising a firstperfume having the structure:

HO l and a second perfume selected from the group consisting ofcitronellyl formate, citronellol, labdanum resin, nerol, menthone,geraniol, trans-decahydro-fi-naphthol, benzoylphenom-artificial musk,phenyl ethyl acetate, benzyl acetate, ionone, phenyl ethyl alcohol andmixtures thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,422,648 6/1947\Rilliams et al. 260-445.]

SAM ROSEN, Primary Examiner.

JULIAN S. LEVITT, Examiner.

I D. GOLDBERG, Assistant Examiner.

4. A PERFUME COMPOSITION COMPRISING 400 PARTS CITRONELLOL, 100 PARTSBENZOYLPHENONE, 60 PARTS PHENYL ETHYL ACETATE, 10 PARTS ARTIFICIAL MUSKAND 200 PARTS OF A PERFUME HAVING THE STRUCTURE